The present invention relates to an oral appliance, a system and a method for correcting a malocclusion. More specifically, the present invention relates to an oral appliance, a system and a method, in conjunction with wearing of the oral appliance, to correct a malocclusion, in particular, mandibular prognathism.
It is generally known to provide dental care to a patient. Typically, the patient may visit, for example, a dentist, an orthodontist or other type of care provider at the office of the care provider. The dentist, for example, may examine the patient using various techniques, including imaging and/or x-raying the oral area and/or jaws. After reaching a diagnosis, the dentist may then provide the patient with an oral appliance to correct the condition of the patient.
In addition to the oral appliance, the dentist may provide the patient with instructions for exercises to perform while wearing the oral appliance. The exercises may cause, for example, the teeth to move toward a corrected position and may assist in correcting the malocclusion. In the case of mandibular prognathism, the oral appliance and the exercises may advance the maxilla, retract the mandible and produce an overjet and overbite which may be ideal to correct and/or prevent a future Class III problem, such as lower jaw excess in the patient.
However, the exercises may be tedious and/or time-consuming for the patient. In some cases, the exercises may cause pain to the patient. Accordingly, the patient may not be motivated to perform the exercises and may abandon them or otherwise not regularly perform the exercises to assist with and/or to correct the malocclusion. As a result, the malocclusion may not be corrected to completion. In other cases, the patient may not have time to perform the exercises. Failure to perform the exercises may prevent or otherwise hinder complete correction of a malocclusion.
For example, one particular condition is prognathism. Prognathism may be the positional relationship of the mandible and/or maxilla to the skeletal body where either of the jaws protrudes beyond a predetermined imaginary line in the coronal plane of the skull. The maxillae may consist of paired maxillary bones or maxilla; or two halves that may be fused at the intermaxillary suture to form the upper jaw. Similarly, the lower jaw or mandible may be a fusion of two halves at the mandibular symphysis. Prognathism may also be used to describe ways that the maxillary dental arches and/or the mandibular dental arches relate to one another, including a malocclusion in which the upper teeth and/or the lower teeth do not align.
In general dentistry, oral surgery, maxillofacial surgery and/or orthodontics, prognathism may be assessed clinically or radiographically using cephalometrics. One or more types of prognathism may result in the common condition of malocclusion including overbite, in which the top teeth and/or the lower teeth of the patient do not align properly. Cephalometric analysis may be the most accurate way of determining all types of prognathism, since such analysis may include assessments of skeletal body, occlusal plane angulation, facial height, soft tissue assessment and anterior dental angulation. Various calculations and assessments of the information in a cephalometric radiograph may allow the clinician to objectively determine dental relationships and/or skeletal relationships and determine a plan of correction.
In particular, mandibular prognathism is a Class III malocclusion with a dentofacial anomaly affecting the lower third of the face. Mandibular prognathism may be characterized by protrusion of the mandible with lower incisors often overlapping the upper incisors. The protruding lower jaw may be caused by a forward positioning of the mandible itself.
To obtain the best results in correcting Angle Class III malocclusions, the etiologies of the malocclusion may first be clarified, and then an appropriate modality may be decided. Angle Class III malocclusions may be classified into three categories. Type A is true mandibular prognathism, which means that the maxilla is normal but the mandible may be overgrown. Type B is characteristic of the overgrown maxilla and mandible with anterior crossbite. Type C indicates a hypoplastic maxilla with anterior crossbite. Modalities may be differentially decided according to the classification of Angle Class III malocclusions.
For many Class III malocclusions, surgery may be the best alternative. Depending on the amount of skeletal discrepancy, surgical correction may consist of mandibular setback, maxillary advancement or a combination of mandibular and maxillary procedures. After surgical correction of the skeletal discrepancy, the occlusion may usually be finished orthodontically to a Class I relationship.
The surgical correction of Class III malocclusion, in particular, mandibular prognathism, may be undertaken in a variety of ways, e.g. a bilateral sagittal split osteotomy to retract the mandible or a Le Fort I procedure to advance the maxilla, or a combination of these procedures. However, the associated surgical risks and complications must be considered, as well as the increased expense.
If a non-surgical alternative may be capable of producing results comparable with those that may be achieved surgically, then a dentist and/or orthodontist may consider and/or suggest such a non-surgical approach to the patient. In some cases, a non-surgical approach may be the preferred choice of the dentist, orthodontist and/or the patient.
For example, facial growth modification may be an effective method of resolving skeletal Class III jaw discrepancies in growing children. Dentofacial orthopedic appliances, including the chin cup, face mask, maxillary protraction combined with chin cup traction and the Frankel functional regulator III appliance may be used. Orthognathic surgery in conjunction with orthodontic care may be required for the correction of mandibular prognathism in an adult patient. Typically, many oral appliances have an upper labial shield and a lower labial shield to receive and/or move the dentition of the patient. In certain cases, either the upper dentition may be moved or the lower dentition may be moved. In other instances, the upper dentition and the lower dentition may be moved. If the upper labial shield may not be provided, then the upper arch and the whole upper dentition may be pushed forward by the appliance.
A need, therefore, exists for a non-surgical approach for correcting mandibular prognathism in a patient of a young age. A need also exists for an oral appliance and a method for reducing an amount of patient cooperation and/or exercises required for correcting a malocclusion, in conjunction with wearing of the oral appliance, to correct a malocclusion, in particular, mandibular prognathism.